Maybe someone can help me. 92 rs camaro 305tbi everything is stock except for the headers and exhaust.
New correct rotation water pump
New aluminum radiator and cap
Custom fan shroud with dual 12 inch fans with switch
New 160 thermostat
New o2 sensor
New fuel filter
Fuel pressure is good at 11.5 psi
No check engine light
All air dam are intact nothing is missing or crack
No ac and condenser is out of*car
50/50 water and antifreeze mix
Lower bottom radiator has a spring
Standard tranny
Check plug and it's running correctly
Check the head gasket and it's good.*
Timing set at 10 degrees at idle
Here's my problem, if I leave the fan on all the time it runs cool around 180-190 in traffic or highway, but as soon as I turn off the fan when I'm on the highway the temperature climb up to 240-250, the only way I can get the temperature to go back down is by turning on the fans and leaving it on. Is this normal for the third generation camaro, I had other cars and never had this problem. And no the water doesn't boiled or leak. Help me

 

One possibility is that your gauge isn't reading accurately. If the air dam is installed that should be enough to cool the car at highway speeds.

 

I'm starting to think its the gauge too, I'm about to buy a new gauge and see if that's the case.